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Infralittoral mixed sediment

Full Hierarchy  >>  SS >>  SS.SMx >>  SS.SMx.IMx

Habitat (physical) description


 Salinity: Full (30-35 ppt), Variable (18-35 ppt) 
 Wave exposure: Moderately exposed, Sheltered, Very sheltered 
 Tidal streams: Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn) 
 Substratum: Mixed sediment 
 Zone: Infralittoral 
 Depth Band: 0-5 m, 5-10 m, 10-20 m, 20-30 m 
 Other Features:  

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Previous code

This biotope occurred in previous versions of the classification as:
IMX.FaMx - Version: 97.06

Distribution of habitat SS.SMx.IMx  Infralittoral mixed sediment
Distribution of habitat SS.SMx.IMx Infralittoral mixed sediment, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

Shallow mixed (heterogeneous) sediments in fully marine or near fully marine conditions, supporting various animal-dominated communities, with relatively low proportions of seaweeds. This habitat may include well mixed muddy gravelly sands or very poorly sorted mosaics of shell, cobbles and pebbles embedded in mud, sand or gravel. Due to the quite variable nature of the sediment type, a widely variable array of communities may be found, including those characterised by bivalves (SMX.VsenAsquAps, SMX.CreAsAn, and SMX.Ost), polychaetes (SMX.SpavSpAn) and file shells (SMX.Lim). This has resulted in many species being described as characteristic of this biotope complex all contributing only a small percentage to the overall similarity (see below). This biotope complex may also include a newly proposed Chaetopterus biotope (Rees pers com.) recently found in the eastern English Channel. This biotope is characterised by an undescribed Chaetopterus sp. and small Lanice conchilega. Further sampling is need in order to assess and fully characterise this potential biotope. As a result, the Chaetopterus biotope has not been included in this revision. Infaunal data for this biotope complex are limited to that described in the biotope SMX.VsenAsquAps and so are not representative of the infaunal component of the whole biotope complex.


No situation data available.

Temporal variation

No temporal data available.

Similar biotopes

Not applicable or unknown.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity Abundance (no.2)
Esperiopsis fucorum O 2
Hydrallmania falcata O 2
Alcyonium digitatum O 3
Cerianthus lloydii O 2
Urticina felina O 5
Nemertea C 3 288
Nematoda F 2 57
Anaitides mucosa C 1 78
Syllidia armata C 3 731
Sphaerosyllis hystrix F 1 39
Aphelochaeta marioni C 4 2002
Caulleriella alata C 2 120
Chaetozone gibber C 3 582
Mediomastus fragilis C 5 675
Notomastus latericeus F 1 85
Melinna palmata A 3 1210
Amphicteis gunneri A 2 276
Lanice conchilega O 3
Sabella pavonina C 7
Pomatoceros lamarcki C 2 178
Pomatoceros triqueter O 1
Tubificoides benedii C 2 500
Tubificoides swirencoides C 2 385
Metaphoxus pectinatus C 1 102
Abludomelita gladiosa F 1 153
Gammarella fucicola F 2 578
Maera grossimana C 3 228
Corophium sextonae C 3 961
Janira maculosa F 1 260
Apseudes latreillii C 7 2520
Paguridae O 3
Pagurus bernhardus O 3
Hyas araneus O 1
Cancer pagurus R 1
Necora puber O 1
Carcinus maenas O 1
Calliostoma zizyphinum R 1
Calyptraea chinensis C 5 351
Crepidula fornicata C 20
Buccinum undatum O 5
Limaria hians A 2
Ostrea edulis O 1
Tellimya ferruginosa F 2 73
Venerupis senegalensis A 2 56
Asterias rubens O 3
Ophiothrix fragilis O 2
Ascidiella aspersa F 2
Styela clava O 3

Example photographs of biotope

No characteristic photos currently available. If you are able to provide a photograph of this biotope please contact .

Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8

Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901